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University of Alberta researchers offer physical evidence for chronic fatigue syndrome

Public release date: 23-Aug-2004

Contact: Phoebe Dey
University of Alberta

A University of Alberta study has verified that there is physical evidence for those who suffer from chronic fatigue syndrome (CFS), giving new weight to the often stigmatized and misdiagnosed disorder.

Research just published in the "International Journal of Psychophysiology" determi­ned that, using independent criteria, CFS can be distinguished from depression--two disorders that share many of the same symptoms.

CFS is an often debilitating disorder, characterized by a constellation of symptoms including fever, sore throat, headache, muscle weakness, myalgias, post-external malaise, sleep and cognitive disturbances. The level of disability varies for people with CFS, but some individuals find they are unable to return to work or function nor­mally on a day-to-day basis. Unfortunately, many of these symptoms are subject­tive in nature and are difficult to quantify or confirm, says Hannah Pazderka-Robin­son, the lead author on the study. Not only does the stigma attached with the disor­der play an emotional toll on the patient, but it has implications for insurance claims as well.

"There are a number of medical professionals who don't believe that CFS exists in the first place," said Pazderka-Robinson. "The problem is, both CFS and depression are characterized by very similar profiles. Imagine a patient who approaches a doctor and tells him they feel depressed and tired all the time.

"Since depression shows a high co-morbidity with CFS, some CFS patients are often given antidepressants--that don't work or work poorly, since they do not address the underlying condition. Again, when these medications don't work, physicians someti­mes jump to the conclusion that there isn't really anything, physically, wrong. Ob­vious­ly, both misdiagnosis and the tendency for doctors to treat these patients as if they're not really sick can be extremely distressing. It can also undermine the pa­tient's trust in the doctor and make them less likely to seek treatment if the condition worsens."

The most significant part of the research was to provide independent verification for CFS sufferers that these patients are different than normal controls and they're not "just depressed," said Pazderka-Robinson.

Numerous psychological investigations have attempted to differentiate these groups, with limited success. The U of A study was the first of its kind to use electrodermal activity-electrodes were placed on each hand- to investigate the differences among CFS, depression patients and healthy controls. Using tone and light stimuli, the results showed that CFS can be discriminated from those with major depression by recordings of skin temperatures and electrodermal activity.

Moreover, the profile of CFS patients is clearly different from normal controls, suggesting there is a clear biological basis to the condition.

Pazderka-Robinson completed this study with researchers from the University Centre for Neuroscience at the University of Alberta and from Alberta Hospital.



Prolonged acetylcholine-induced vasodilatation in the peripheral microcirculation of patients with chronic fatigue syndrome.
Clin Physiol Funct Imaging. 2003 Sep;23(5):282-5.

Khan F, Spence V, Kennedy G, Belch JJ.

Vascular Diseases Research Unit, University Department of Medicine, Ninewells Hospital and Medical School, Dundee, UK.

Although the aetiology of chronic fatigue syndrome (CFS) is unknown, there have been a number of reports of blood flow abnormalities within the cere­ral circulation and systemic blood pressure defects manifesting as orthostatic intolerance. Neither of these phenomena has been explained adequately, but recent reports have linked cerebral hypoperfusion to abnormalities in choli­ergic metabolism. Our group has previously reported enhanced skin vasodila­ation in response to cumulative doses of transdermally applied acetylcholine (ACh), implying an alteration of peripheral cholinergic function. To investiga­e this further, we studied the time course of ACh-induced vasodilatation follo­ing a single dose of ACh in 30 patients with CFS and 30 age- and gender-mat­ched healthy control subjects. No differences in peak blood flow was seen be­tween patients and controls, but the time taken for the ACh response to re­cover to baseline was significantly longer in the CFS patients than in con­rol subjects. The time taken to decay to 75% of the peak response in patients and controls was 13.7 +/- 11.3 versus 8.9 +/- 3.7 min (P = 0.03), respecti­ely, and time taken to decay to 50% of the peak response was 24.5 +/- 18.8 ver­sus 15.1 +/- 8.9 min (P = 0.03), respectively. Prolongation of ACh-induced vasodilatation is suggestive of a disturbance to cholinergic pathways, per­aps within the vascular endothelium of patients with CFS, and might be related to some of the unusual vascular symptoms, such as hypotension and orthostatic intolerance, which are characteristic of the condition.

PMID: 12950326 [PubMed - indexed for MEDLINE]